Since I am out of the mining biz, I have the following turnkey outfit for sale.   Perfect kit for outfitting a new location.    Run a circuit, plug in and go.   All the pieces are there.

4 Avalon 841s with power supplies
Raspberry PI 3B controller (sans microSD card of course)
AUC with daisy chain cables
Tripp-lite Power strip
Power cords
L6-30 pigtail on the power strip
L6-30 outlet

And if you have a Cutler Hammer panel I'll send along the 30amp breaker too. 

Everything was operating perfectly late feb/early march with no issues: 53-54 TH performance.  In the photo below Raspberry Pi controller was on my desk getting dusted so is not seen there but is part of the deal.




Since I seem to have lost out on the opportunity to make $521 but not hanging on till a coin was found; I am asking $521 plus actual shipping charges.  . PM me directly.  I only get to log in once a day if that much so be patient on a reply.   Many thanks!

Not really.

Assuming 5ND was kept instead of changed to 3 days in Jan:

Say you had 54TH mining end of Feb, and turned them off March 1st, ramp down time was around 146 days in Jan, it would have been more in March, but for arguments sake lets keep it the same.

Block was found on 2th May, which is 81 days after you turned off your miners. So by then you would have ramped down by at least 55% or roughly 24TH.

Pool N avg was 7.45PH when the block was found and the block was worth 8.31423879 BTC

So your pool reward percentage would have been 0.024/7.45*100 which equals 0.322147651%

That's 8.31423879 x 0.322147651% or 0.026784125 BTC

BTC price was aprox $9750 so the most you could have lost was pretty much $261

If you would have kept mining the entire time after the switch to 3 days you would have made 0.05356825 or around $522 when the block was found in May






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Thanks for the great write-up.   The extra 81 days of electricity would have been significantly more than $522.   Just a matter of how much I wanted to loose I guess.  The halving hurt as much 5->3nd

Well that sux.   Guess I should have consulted here before disconnecting; but then again it would not have changed my decision - the 220V circuit  powering the miners had to got for another piece of equipment and offices were being added and the fan noise would have been unacceptable.   So I didn't really have a choice.  I could have spun up another location but my miners were already marginally profitable "normal" luck so it would not have been worth it.

Guess I am just out 800-900$

I've never really understood the 5Nd  thing, but always loved the pool.  Alas, I had to quit mining back late Feb/early March for a couple of reasons; difficulty passing profitability being the main reason (electric rate increase too).   But there were other show stoppers; like the use of the building changed and noise pollution was unacceptable.

So when I quit I was contributing 54TH and had helped on the first ~150% of the most recently found bitcoin.    So I expected at least a little something in the payout but received nothing - Did my work really expire and my $~800 in electricity from mid-December - end Feb just fly away on the wind ?

Thanks for any explanation!

NCDiesel

Quick update. I moved the miners to a shelving unit directly in front of a window. And I situated the miners so their exhausts go straight out the window. This completely solved my problem. My intake and chip temperatures improved dramatically.  By the way, my windows have screens so shouldn’t have any issues with bugs, etc.   I can’t wait for winter so that my miners heat my shop and I can save money on heating :-)

[later edit]   By the way, I determined the real root cause was this:  Even though the shop is large(40'x30'), the miners were in the corner and blowing exhaust out along the 40' wall.  The exhaust then however continued around the shop, creating a a swirl that circled the entire shop and the miners were then swallowing their own only slightly cooled exhaust after it made a round trip.  Apparently opening all the windows disrupted it only a bit unless it was a windy day.   In fact, a recent very windy day saw substantial improvements in the intake temps and that is when I had my "ah-ha!" moment.

First - are you sure its 220V?   Current electrical national electrical code for single phase is 120V/240V   I always see 235-240V at the wall.  Three phase or really old electrical co-ops will/may give other, lower "2 leg" voltages.  It makes a difference in your case:

Lower voltage:
1400W / 220V = 6.36A then (3 x 6.36) + 2.0(10% of breaker size as safety factor) = 21.08 amps  )-:

Higher voltage:
1400W / 240V = 5.83A then (3 x 5.83) + 2.0(10% of breaker size as safety factor) = 19.49 amps (-:


As you can tell - you could run three WITHOUT changing the breaker if it is 240.

Couple of caveats:
I am not a electrician
Only you and your electrician know if this actually makes sense for your circumstance.
If you upgrade to 25AMP, make sure your plug is rated for 25Amp too.

Hope this helps!

I had two related questions, but first let me set the stage:

Got 4 new 841s, and at the same time sold my old 741 to a friend.  Everything been great for both of us for a few weeks, but for a reason(s) neither of us understand, the settings in the controller I sold to him reverted late last week to my old settings.  So you guessed it - I got credited with his machine's work since the old settings obviously had my worker info until he fixed it this morning:

Question #1:  Any easy way to split out the work?   This is more theoretical than practical - I'm just going to buy him lunch to pay him back but I was curious if there was an easy way to do this if the parties have a agreement on hash rate share (ie I am 4.5 machines he is .5).

Question #2:  While computing on my worker, his machine caused my average "Shares" count to double; yet the "Average Share" value fell by half.   Clearly I don't understand these values like I thought.  I would expect all values to change by a percentage value commensurate with the the incremental hash rate.  Could someone explain how those are calculated?

https://imgur.com/gallery/Pfl2g

Thanks!

Assuming your 12 words in the picture are actually expressed in a way that resembles captchas, Severos concerns - while are plausible and valid - are not likely in this specific scenario so I wouldn't worry too much.  Software would be pretty useless because not only are captcha solvers way less than 100%, they are terrible at finding captcha riddles in the first place in non-discreet contexts.  And I doubt anyone would bring out the big-gun NSA image analyzers for 500$USD of bitcoin.   However, if your words are plain text  then yes - someone with software will be the winner and it will happen minutes after you open it.

The delta thing is simply the technique that would be used to shorten any processing time you might try to introduce by changing the image at the last minute.

Hope this helps,

This next block will be the first with all shift performance from my new 841s outside the 5nd ramp.   So If you can't solve a block for yourself or your country ; do it for me:  Block Tuesday!

By the way - forgot to thank you for that link.   My shop is completely open and the warm air mixes fairly completely.  So there is no cooler area to move air to, but that ventilation fan you posted a link to has my gears turning - I may be able to rig something up yet.

Thanks again

Thanks - so I dropped it back to 50% and even with ambient temps in the 68-70 degree range the fans ran back up to to 90+%   I guess unless you have your farm in the north pole you end up with ~ 100% fans anyways.

https://imgur.com/a/FTJiO

One more question:   The minimum fan percentage that my installation of the controller firmware defaulted to was 100%.   The mini-documentation beside the field on the page says the default value is 10% but it burnt into my controller with 100%.

So my fans my on 4 841 miners run full blast constantly, even on these cool nights where chip temps are in the 50/60C range.  Should I change it to the default so I will get variable fan control?  Or did Canaan realize these 841s need 100% fan all the time?

Thanks again!

As for exhausting air....

I have a handy window right by the miners.   I was thinking of a cuff around the fan end of each miner, 6" flex tube about 8-10' long from each miner, to individual vents for each miner - mounted in plywood mounted in the window. 

It would be two right angle turns tho.   Can the miner fans drive exhaust through two turns and 8-10' of tube?'   Or would I be creating too much back pressure?  I have limited(read: none) experience with this kind of stuff so I needed someone with more experience to tell me if this is OK or if I need a "helper" fan at the window/plywood side helping to draw air.

Thanks!

PS: I have a screen in the window and therefore can do without dryer vent type exhaust port.  But the screen might create additional back pressure???

Ive determined my problem is all ambient temps(moving the power supplies helped a bit).   We had 2-3 days above average in terms of temps.  A nice cold front moved through and we are in the 40s and dropping fast.   So I opened the shop up completely for a few hours and clearly the temps moderated. 

I think this means I need to exhaust the miners to the outside when summer comes.

https://imgur.com/a/YfiY9

Thanks,

Thanks - Having much lower numbers on my single741 led me to believe that maybe my environment wasn't conducive to 4 841s.


I'll keep an eye on them - thanks for the sanity check!

Thanks - heat was not an issue with my single 741 proof-of-concept project (yes I ease into things).   So when I expanded the project to 4 841s I assumed I would have (4miners  X (0 heat issues) ) with the 841s.   Definitely bad math.

Still hashing around 54THs - nice machines for sure.....

I do have the exhaust flow free to the main area of the shop - in fact I can feel the flow/heat across the shop (nearly 40'!)

First a question:   What is the procedure for powering down?   Is there a proper way to power these down in a way that keeps the fans running until they are cool?

Thanks for all the replies.  It appears they are scavenging air from/over the power supplies, which are situated "inline" (front to back rather than side by side).  This is because I opted for a floor space minimizing shelf design with really wide, but shallow, shelves.  So I put the power supplies on their side and beside the miner to get them out of the air flow - can power supplies be on their side?   Moving them out of the way dropped the temps a few degrees on the worst one but thy are still around 80-83.  Otherwise they would need to be on top of, or under, the miner which just seems like a bad idea.  Wish they power cables were longer.  Its nearly impossible to situate the power supply exhaust out of the general area of the miner intake.

https://imgur.com/a/1xAGa

Thanks!

PS:  I added a re-circulating fan (big shop style pedestal fan ) and it did not help.

So my machines have been happily hashing for a few hours now, and my hash rate has been very good. Looking like about 5% above the specs averaged across the machines. However the temperature has me concerned. The fans  maxed out at 100% nearly immediately upon beginning hashing and I have temperatures in the low 80s (F) according to the controller. Ambient temperatures in the shop are around 70F  So it seems it should be able to keep the temps down.  The shop is an open design, it is 1200 ft.², has 10’ ceilings, and has lots of metal and concrete in it to act as a heat sink.

Can you folks take a look at this image and let me know what you think? Should I be concerned about the temperatures?

http://imgur.com/1mo3EyX

Thanks!

And the winner is.....

As soon as you mentioned the power vs data I knew what I had done.    I had grabbed the charging cable for a hand held trouble light I have in my shop.


Hashing out on all 4 miners now - thanks!!!

PS:  Also had a bad network patch cable when I set up the controller.  Fortunately noticed right off the bat because the light flickered but still - two bad cables on the same project - who would have thought....

Wallwart is one of those push-button Raspbery pi power cables:

http://a.co/iZMroji

The LED colors on the miner, being green, seem to indicate a normal power up.  AUC3 green is "normal".  So I don't think there's anything useful in the LEDs.

No errors in the system, kernel or API logs.   In fact, the API log just records the pool transactions.   There seems to be absolutely nothing from the miners.   

On the CGIMiner status page no devices show up - just the pool information.

All the controller information pages looks for all the world like it does when the miners are powered off.

Hope this helps...